Originally Posted by
manneca
Do not spend even one night in Narita. Unless you are getting in really late at night or leaving really early in the morning. There isn't anything to do.
I'd suggest looking at the JR rail pass. You can use it on trains in Tokyo and Osaka. And probably elsewhere.
Unless I were arriving really late at night, I'd head into Tokyo for a couple of days. Hit Shinjuku and other youth places (check a guide book, I'm 65).
Head up to Nikko, Hiroshima, Osaka, Kyoto, Kagashima. Gee, just get a guide book and go wherever your fancy takes you.
I like Dorling Kindersley guide books cause they have pictures.
The JR Pass is great for traveling from city to city, but useful only on JR trains (basically the commuter loop lines and the airport express trains) within Tokyo and Osaka. It is not good for traveling on subways or other non-JR lines anywhere.
To decide whether you need a JR Pass or not, go to Hyperdia.com and figure out what your proposed itinerary would cost with single tickets. Then see what a pass for that same time period would cost.
For example, on my upcoming trip, I will be traveling from Tokyo to Hiroshima for a conference and then making a leisurely return to Tokyo via Shikoku. In my case, a JR Pass is definitely worth the money and affords me the freedom to make last-minute changes.
However, for someone who is flying into NRT, staying in Tokyo, taking the Shinkansen one way to Kyoto, and flying out of KIX, the JR Pass is not a good deal.